An ESIPT-based NIR-emitting ratiometric fluorescent probe for monitoring hydrogen peroxide in living cells and zebrafish

Hydrogen peroxide (H2O2) is closely related to a variety of human diseases. It is a challenge to dynamically monitor biological H2O2 activity. Hence, we design and prepare a NIR-emitting ratiometric fluorescent probe (HBQ-B) for detecting H2O2 according to the excited-state intramolecular proton transfer (ESIPT) mechanism using the benzyl boronic pinacol ester group as a recognition unit. HBQ-B displayed specificity toward H2O2 over other bioactive analytes. Meanwhile, HBQ-B exhibited a good linear relationship between the fluorescence ratio (I656/I538) changes and the concentrations of H2O2 (0–10 μM). HBQ-B also showed a large Stokes shift (234 nm) and a marked detection limit (40.2 nM). HBQ-B was utilized to image the intracellular H2O2 in living MCF-7 cells, HeLa cells and macrophages (RAW 264.7 cells), respectively. In addition, HBQ-B was used to monitor the dynamics of H2O2 level changes during zebrafish development. In this work, a NIR-emitting ratiometric fluorescent probe, HBQ-B, according to the ESIPT mechanism using the benzyl boronic pinacol ester group as a recognition unit, has been prepared. HBQ-B shows the sensitive and selective detection of H2O2 through a green-to-red fluorescence response. It is employed to visualize both exogenous and endogenous H2O2 in living HeLa cells and MCF-7 cells and macrophages (RAW 264.7 cells), respectively. HBQ-B also exhibits the well-performance measurement of H2O2 in zebrafish. [Display omitted] •An ESIPT NIR-emitting ratiometric fluorescent probe, HBQ-B, for monitoring H2O2 has been designed and synthesized.•HBQ-B shows a low detection limit of 50.8 nM and a marked Stokes shift (291 nm).•HBQ-B is capable of monitoring the variation of endogenous H2O2 levels during zebrafish development.